This proposal is a further study on the association between persons with genetic disorders or with advanced age and high risk of cancer. Hematopoietic or fibroblastic cell lines derived from various persons will be used. The difference in growth pattern, chromosome changes, sensitivity to virus infection and chemical treatment, and susceptibility to cell transformation by viral or chemical agents in cell lines derived from persons with high risk of cancer and lines from normal individuals will be studied. The results of these studies may help in developing methods for detecting individuals with a high expectancy of cancer and in understanding some aspects of preneoplastic disposition.